CuAl2O4 powder synthesis by sol-gel method and its photodegradation property under visible light irradiation

Nanocrystalline spinel CuAl2O4 powders were prepared by sol-gel method from nitrate Cu(NO3)(2) (.) 3H(2)O, Al(NO3)(3)(.)9H(2)O and complex (C6H8O7H2O)-H-.. Sintering was carried out at 400, 500, 600, 700, 800 degrees C respectively for 2 h in air. The XRD patterns started to appear CuAl2O4 peaks after sintering of 500 degrees C and consist of only CuAl2O4 peaks as spinel crystal after sintering of 700 degrees C. The powders were analyzed by TEM and UV-vis diffuse reflectance spectrum to be round, about 10-30 nm in size and Eg = 1.77 eV. Photodegradation property of nanocrystalline CuAl2O4 powders was investigated by using methyl orange as model pollutant and mercury lamp (lambda > 400 nm) as energy source. The results indicated that CuAl2O4 powders sintered at 700 degrees C had the excellent visible photocatalytic property. Under the irradiation of visible light, methyl orange could be degraded 97% in 120 min.